Sintered sprocket and manufacturing method

摘要

A sintered sprocket, with a tempered martensitic structure; the residual austenitic structure being 10-50 vol % of the tooth surface layer. The composition of, at least, the tooth surface layer of the sprocket comprising: (by mass %) C: 0.6-1.2 N: 0.05-0.5 Ni/Cu/Mo: 0.5-5 The remainder Fe and other impurities. The density of the tooth surface layer may be a least 7.4 g/cm<3>. A method of manufacturing a sintered sprocket comprising a carburisation-nitriding quenching step is also disclosed. Such method comprising: the carburisation and nitrogenisation of the sprocket at a temperature of 800-950{C followed by tempering, where the quenched sprocket is tempered at 140-220{C.